By 1929, more than 4,000 workers were employed on site for the manufacture of advanced machinery used to outfit Naval warships. Most of the workers lived just blocks away; a neighborhood of hard-working skilled African-American and Eastern European families existed in the northwestern portion of the site until the 1940's. By the early 1940's, with the threat of a second World War looming, the Navy Yard Annex grew again to include land west to 1st Street--the current western boundary of The Yards--including some of the homes formerly occupied by Navy Yard laborers.